Image pick-up tube target

Abstract

There is disclosed an image pick-up tube target comprising an N-type conductive film formed on a transparent substrate, and a P-type photoconductive film in rectifying contact with the N-type conductive film and comprising a first layer containing As and Se, the average concentration of As in the first layer being below 8% by weight, a second layer containing As and Se, a third layer containing As and Se, the concentration of As being in the range of 8 to 20% by weight and thickness of the third layer being in the range of 5 to 50% of the total thickness of the P-type photoconductive film, in the order named, and a beam landing layer.

What is claimed is: 
     
       1. An image pick-up tube target comprising an N-type conductive film formed on a transparent substrate, and a P-type photoconductive film in rectifying contact with said N-type conductive film and comprising a first layer containing As and Se, the average concentration of As in the first layer being below 8% by weight, a second layer containing As, Te and Se, a third layer containing As and Se, the composition of said third layer being different along the direction of thickness thereof, a fourth layer containing As and Se, a fifth layer containing As and Se, the concentration of As being in the range of 8 to 20% by weight and the thickness of said fifth layer being in the range of 5 to 50% of the total thickness of said P-type photoconductive film, in the order named, and a beam landing layer. 
     
     
       2. An image pick-up tube target according to claim 1, wherein the concentration of As in said first, second, and fourth layers is in the range of 2.5 to 6% by weight, the concentration of As in said third layer decreases continuously along the direction of thickness toward said fourth layer. 
     
     
       3. An image pick-up tube target according to claim 2, wherein said beam landing layer is made of Sb 2  S 3 . 
     
     
       4. An image pick-up tube target comprising an N-type conductive film formed on a transparent substrate, and a P-type photoconductive film in rectifying contact with said N-type conductive film and comprising a first layer containing As and Se, the average concentration of As in the first layer being below 8% by weight, a second layer containing As, Te and Se, a third layer containing As and Se, the composition of said third layer being different along the direction of thickness thereof, a fourth layer containing As and Se, a fifth layer containing As and Se, the concentration of As in said fifth layer being larger than that of As in a portion of said fourth layer near a boundary between said fourth layer and said fifth layer and being in the range of 8 to 20% by weight and the thickness of said fifth layer being in the range of 5 to 50% of the total thickness of said P-type photoconductive film, in the order named, and a beam landing layer. 
     
     
       5. An image pick-up tube target according to claim 4, wherein the concentration of As in said first, second, and fourth layers is in the range of 2.5 to 6% by weight, and the concentration of As in said third layer decreases continuously along the direction of thickness toward said fourth layer. 
     
     
       6. An image pick-up tube target according to claim 5, wherein said beam landing layer is made of Sb 2  S 3 .